Total PA Research Articles

Accelerometer-based physical activity levels among Mexican adults and their relation with sociodemographic characteristics and BMI: a cross-sectional study.

BackgroundThe objectives of this study were to describe the accelerometer based total and bout-specific PA levels for a representative sample of adults from Cuernavaca, Mexico, and to examine the relationships with sociodemographic characteristics and BMI status.MethodsCross sectional study of adults from Cuernavaca, Mexico (2011, n = 677). Participants wore Actigraph GT3X accelerometers for seven days and sociodemographic data was collected through a survey. Weight and height were objectively measured. Total minutes/week of moderate-to-vigorous PA (MVPA) and of MVPA occurring within bouts of at least ten minutes were obtained. Intensity-specific (moderate and vigorous) total PA and bouted-PA was also obtained. The relation of each PA variable with sex, age, socioeconomic status, education, marital status and BMI status was assessed using unadjusted and adjusted linear models.ResultsThe mean total MVPA among adults from Cuernavaca was 221.3 ± 10.0 (median = 178.3 min/week). Average MVPA within bouts was 65.8 ± 4.7 min/week (median = 30.0 min/week). 9.7 % of total MVPA occurred within bouts. Significant associations were found for total and bout-specific MVPA with being male (positive) and owning a motor vehicle (negative). Additional associations were found for intensity-specific PA outcomes. Mexican adults were more active during weekdays than weekends, suggesting that PA may be more strongly driven by necessity (transport) than by choice (leisure).ConclusionsThis is the first study to objectively measure PA for a representative sample of Mexican adults in an urban setting. The sociodemographic correlates vary from those known from high income countries, stressing the need for more correlate studies from lower-to-middle income countries.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-015-0243-z) contains supplementary material, which is available to authorized users.

Impacts of surface inclination on the vertical loading rates and landing pattern in novice barefoot runners

Diet, Cancer and Health study. The cohort was established in 1993–1997 and follow upswere conducted in 1999–2002 and 2010–2011. PA was measured at baseline (before diagnosis) and after diagnosis. Delayed entry cox proportional hazards models were used to calculate hazard ratios (HR) for overall survival according to pre diagnosis PA, post diagnosis PA, and changes in PA from before to after diagnosis. For all three analysis PA was applied as total PA, recreational PA and household PA. Results: For post diagnosis PA we found a reduction in overall mortality in multivariate analysis for the second quartile of recreational PA (HR 0.48, 95% confidence interval (CI) 0.29–0.79), and for the fourth quartile (HR 0.53, CI 0.29–0.97) using the first quartile as reference. No clear associations were found for household PA in either of the three analyses. In pre diagnosis PA and change in PA no significant associationwith survivalwas found, although a tendency was seen for change in recreational PA, that the groups with increased and unchanged high levels of recreational PA had reduced risk of mortality (26% and 34% respectively). Conclusion(s): Our study suggests that post diagnosis recreational PA at least moderate levels may reducemortality after BC, whereas household activities does not seem to be associated. Implications: Seen in the perspective of the existing evidence, it can be suggested that participation in recreational PA after diagnosis may be beneficial for survival regardless of level of PA prior to diagnosis.

Associations of Daily Physical Activity and Sedentary Behavior with BMI in Older Women

To sustain a healthy weight, 75-150 mins/wk of moderate-vigorous intensity physical activity (MVPA) are recommended. As PA declines with age, accurate PA measurement in older adults is crucial but challenging. Recent reports suggests that too much sedentary time also affects weight and distributing PA (including low intensity; LPA) throughout the day is important in addition to total PA time. PURPOSE: To determine the importance of considering PA variations during the day for BMI management in older women. METHODS: Eleven older women (age 77±9 yrs; BMI 26±5 kg/m2) wore activity monitors, each containing a tri-axial accelerometer (±16g, 100 Hz), on the waist and ankle for 4 days in the free-living environment. IRB approved the protocol and written informed consent was obtained. Daily step counts, active time (classified as MVPA for cadence>94 steps/min) and sedentary break number (number of activity segments ≥30 s) were estimated from acceleration data using a previously validated algorithm. The parameters’ total daily values and coefficient of variations (CoVs) of hourly values (to quantify variation during the day) correlations with BMI were assessed with linear regression. RESULTS: BMI was inversely correlated with active and MVPA time, step counts, and sedentary break number (Fig 1) consistent with associations of greater activity with healthier weight. BMI was positively correlated with the CoVs of active time/hour, step number/hour, and sedentary break number/hour (Fig 1), with higher r2 values compared to daily totals. CONCLUSION: The data highlight the importance of breaking up sedentary time with both LPA and MVPA, and distributing PA throughout the day to sustain a healthy BMI. Funded by DOD DM090896 and NIH RO1 AR027065.

Describing the Intrapersonal Influences on Eating Behaviours of Adolescent Girls in Saudi Arabia

s / Can J Diabetes 39 (2015) S38eS74 S39 needed to achieve a reliability of 0.80. There were no differences between weekdays and weekend days in mean total PA (205 (95% CI: 187-222) vs. 210 (95%CI: 192-228); p1⁄40.70) or in mean MVPA minutes 26 (95%CI: 20-32) vs. 29 (95%CI: 23-36); p1⁄40.45). Conclusions: Any 2 weekdays or weekend days of accelerometer monitoring can be used to assess usual PA in children 5 years and under. The use of a simpler protocol may improve compliance and feasibility for studies of PA in early childhood.

The Impact of Generation Status on Weight of Immigrant and Non-Immigrant School-Aged Children Living in Minority Situation: Preliminary Results

s / Can J Diabetes 39 (2015) S38eS74 S39 needed to achieve a reliability of 0.80. There were no differences between weekdays and weekend days in mean total PA (205 (95% CI: 187-222) vs. 210 (95%CI: 192-228); p1⁄40.70) or in mean MVPA minutes 26 (95%CI: 20-32) vs. 29 (95%CI: 23-36); p1⁄40.45). Conclusions: Any 2 weekdays or weekend days of accelerometer monitoring can be used to assess usual PA in children 5 years and under. The use of a simpler protocol may improve compliance and feasibility for studies of PA in early childhood.

Length of moderate-to-vigorous physical activity bouts and cardio-metabolic risk factors in elementary school children

BackgroundAccumulating moderate-to-vigorous physical activity (MVPA) in bouts of 10min is associated with improved cardio-metabolic risk factors (CMRF) in adults. PurposeTo assess the association between the lengths of MVPA bouts and CMRF in elementary school age children. MethodsThe sample included 396, 2nd and 3rd grade students from eastern Kansas (182 boys, 214 girls; age 7.6±0.6years; Body Mass Index Percentile [BMI%ile]: 61.6±9.3) in the fall of 2011. Analyses were conducted in 2014. MVPA bouts were defined as sporadic (<5min), short (5–<10min) or medium-to-long (≥10min). Latent profile analysis was used to identify distinct subgroups (classes) based on the composition of MVPA bouts. Bayesian probability-based Wald chi-square test was used to compare CMRF between classes controlling for age, sex, BMI%ile, and total moderate and total vigorous PA. ResultsThree classes of accumulated physical activity were identified: A (n=78); 97% sporadic 2%, short, 1% medium-to-long bouts; B (n=174); 93% sporadic, 5% short, 2% medium-to-long; C (n=144); and 86% sporadic, 9% short, 5% medium-to-long bouts. Class C had significantly lower BMI%ile (57.3±2.3 (SE)), waist circumference (WC; 55.8±0.5cm) compared with Class A (BMI%ile=70.9±0.5, p<0.01.030, WC=61.0±1.0cm, p=0.<0.01). Class B had significantly lower WC (56.6±0.6cm), p<0.01 than Class A. No significant differences between classes were shown in other outcomes. ConclusionChildren who accumulated MVPA with a higher percentage of short (5–<10min) and medium-to-long bouts (≥10min) had lower BMI%ile, and WC compared with children who accumulated MVPA with a lower percentage short and medium-to-long bouts.

Physical activity levels and obesity status of Oregon Rural Elementary School children

ObjectiveTo evaluate the relationship between physical activity (PA, min/school-day) at school and body mass index (BMI, kg/m2) among rural elementary-aged children. MethodsHeight (cm), weight (kg), and PA were measured for 1767 children (5–12years) enrolled in six rural Oregon elementary schools in fall, 2013. PA at school was measured over four days using Walk4Life pedometers. Children with ≥3 valid monitoring days (n=1482) were included in analyses. Means (min/d) were calculated for wear time, total PA (TPA: combined light, moderate, vigorous PA), and moderate to vigorous PA (MVPA: step count>120/min). BMI z-scores were calculated and regression models were run to examine the relationship between PA and BMI z-scores, adjusting for wear time, sex, and grade. ResultsOverweight (38.1%: BMI≥85th percentile for age and sex) and obesity (19.4%: BMI≥95th percentile) prevalence was similar for boys (n=782) and girls (n=700). More MVPA was associated with lower BMI (P<0.001), independent of sex, wear time or grade. Mean MVPA was 18.9+/−8min/d, versus 15.2+/−6.7min/d for healthy-weight and obese children, respectively. ConclusionsChildren are not meeting minimum MVPA recommendations (60min/d) during school hours. Efforts to promote PA for obesity prevention in rural elementary schools should focus on increasing opportunities for MVPA.

A High Speed Low Power Adder in Multi Output Domino Logic

Speed and power is the major constraint in modern digital design. We have to design the high speed, l ess number of transistor as a prime consideration. The low power c arry look ahead adder using static CMOS transmission gate logic that overcomes the limitation of series connected pass t ransistors in the carry propagation path. In this approach it is required to find the longest critical paths in the multi-bit ad ders and then shortening the path to reduce the total critical pa th delay. The design simulation on microwind layout tool shows the worst-case delay in ns and total power consumption in microwatt range.

Physical activity levels and energy expenditure in urban Serbian adolescents--a preliminary study.

The aim of this study was to evaluate the level of PA and EE in Serbian urban adolescents, using an objective measure. In particular, we explored gender and weight status related differences in PA level and EE among Serbian adolescents. In addition, their PA and EE obtained during schooldays and weekends were compared. From the representative sample of elementary schools in Belgrade, one school was selected by random sampling for the purpose of the objective PA assessment. The sample included 115 students (53 boys and 62 girls) of the average age 14.0 (0.6) years. EE and the duration of PA levels were assessed by the Sense Wear PRO3 Armband device (Body Media Inc., Pittsburgh, PA, USA). IOTF cut-off points were used to define subjects as non-overweight, overweight or obese. Analysis of variance was applied to examine the impacts of gender and weight status on EE and PA duration. Adolescents spent most of the time in sedentary regime 241.7 ± 62.8 min/day, on average and they were totally physically active for 196.0 ± 73.5 min/day. Boys accumulated more PA than girls and during schooldays, the PA of all adolescents was higher than during weekend days. OW girls spent less time in total PA, MPA, and VVPA. On the other hand, NW and OW boys differed only in VVPA. Consequently, OW girls had lower energy expenditure compared with their NW peers, but no such differences in boys were found. The results of this study indicate that low PA activity might be a more important factor in propagation of overweight in girls than boys, at least in early adolescent period. PA in girls should be strongly encouraged, with a special focus on vigorous PA during weekends.

The association between objectively measured physical activity and academic achievement in Dutch adolescents: findings from the GOALS study.

The main goal of this study was to investigate the association between objectively measured physical activity and academic achievement in adolescents. Students in Grades 7 and 9 (N = 255) were included. Overall, we found no significant dose-response association between physical activity and academic achievement. However, in Grade 7 total physical activity volume (Total PA) was negatively associated with academic achievement, while moderate-to-vigorous intensity physical activity (MVPA) was negatively associated with both academic achievement and mathematics performance. In contrast, in Grade 9 both Total PA and MVPA were positively associated with mathematics performance. In addition, the overall association between MVPA and academic achievement followed an inverted U-shaped curve. Finally, Total PA was positively associated with executive functioning, while executive functioning in turn mediated the associations between Total PA and both academic achievement and mathematics performance. These results indicate that the association between physical activity and academic achievement in adolescents is complex and might be affected by academic year, physical activity volume and intensity, and school grade.

Combining GPS, GIS, and accelerometry to explore the physical activity and environment relationship in children and young people - a review

The environment has long been associated with physical activity engagement, and recent developments in technology have resulted in the ability to objectively quantify activity behaviours and activity context. This paper reviews studies that have combined Global Positioning Systems (GPS), Geographic Information Systems (GIS) and accelerometry to investigate the PA-environment relationship in children and young people (5–18 years old). Literature searches of the following bibliographic databases were undertaken: Sportdiscus, Medline, Embase, CINAHL, Psychinfo and Applied Social Sciences Index and s (ASSIA). Fourteen studies met the inclusion criteria, and covered topics including greenspace use, general land use, active travel, and the built environment. Studies were largely cross-sectional and took place across developed countries (UK, USA, Canada, New Zealand, and Australia). Findings suggest that roads and streets, school grounds, and the home location are important locations for total PA, and moderate to vigorous PA (MVPA). The relationship between greenspace was positive, however, multiple definitions and outcome measures add complexity to the results. MVPA was more likely in those exposed to higher levels of greenspace compared to sedentary individuals. Total MVPA time in greenspace is low, but when framed as a proportion of the total can be quite high. Domestic gardens may be an important area for higher intensity activity.Researchers are encouraged to show transparency in their methods. As a relatively new area of research, with ever-evolving technology, future work is best placed in developing novel, but robust, methods to investigate the PA and environment relationship. Further descriptive work is encouraged to build on a small but increasing knowledge base; however, longitudinal studies incorporating seasonal/weather variation would also be extremely beneficial to elicit some of the nuances associated with land use. A greater understanding of geographic variation (i.e. within and between countries), as well as urban/suburban and rural dwelling is welcomed, and future work should also include the investigation of psycho-social health as an outcome, as well as differences in socio-economic status, sex and adiposity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12966-014-0093-0) contains supplementary material, which is available to authorized users.

AB1168-HPR Physical Inacivity in Adults with Rheumatic Diseases

BackgroundPhysical inactivity is a frequent complication of rheumatic diseases, and also common in the general population. However, there is surprisingly little research available comparing daily life physical activity between patients...

Primary aldosteronism and essential hypertension: Assessment of cardiovascular risk at diagnosis and after treatment

Background and aimsPrimary aldosteronism (PA), the most frequent form of secondary hypertension, is characterized by a higher rate of cardiovascular (CV) events than essential hypertension (EH).Aim of the study was to evaluate the cardiovascular risk according to the ESH/ESC 2007 guidelines, in patients with PA and with EH, at diagnosis and after treatment. Methods and resultsWe prospectively studied 102 PA patients (40 with aldosterone producing adenoma-APA and 62 with idiopathic hyperaldosteronism-IHA) and 132 essential hypertensives at basal and after surgical or medical treatment (mean follow-up period 44 months for PA and 42 months for EH).At baseline evaluation the stratification of CV risk was significantly different: the predominant risk category was the high CV risk (50% in total PA, 53% in PA matched for blood pressure values and 55% in EH), but the very high risk category was twice in PA than in EH patients (36% in total PA and 33% in matched PA vs. 17% in EH, p < 0.05). The worse risk profile of PA was due to a higher prevalence of glycemic alterations, metabolic syndrome and left ventricular hypertrophy (LVH) (p < 0.05).After adequate treatment, the CV risk was significantly reduced becoming comparable in PA and in EH patient due to a reduction of hypertension grading, prevalence of metabolic syndrome, hypertension persistence and LVH (p < 0.05). ConclusionPatients with PA present a high CV risk, which is in part reversible after specific treatment, due both to the reduced blood pressure values and to the improvement of end-organ damage.

Assessing Preschool Children’s Physical Activity: How Many Days of Accelerometry Measurement

The purpose of this study was to determine the minimum number of days of accelerometry required to estimate accurately MVPA and total PA in 3- to 5-year-old children. The study examined these metrics for all days, weekdays, and in-school activities. Study participants were 204 children attending 22 preschools who wore accelerometers for at least 6 hr per day for up to 12 days during most waking hours. The primary analysis considered the intraclass correlation coefficient (ICC) for each metric to estimate the number of days required to attain a specified reliability. The ICC estimates are 0.81 for MVPA-all days, 0.78 for total PA-all days, 0.83 for MVPA weekdays, 0.80 for total PA-weekdays, 0.81 for in-school MVPA, and 0.84 for in-school total PA. We recommend a full seven days of measurement whenever possible, but researchers can achieve acceptable reliability with fewer days, as indicated by the Spearman-Brown prophecy: 3-4 days for any weekday measure and 5-6 days for the all-days measures.

Interrelationships between eating behavior self efficacy and weight loss

Eating behavior self efficacy (SE) may predict weight loss ability and may improve with weight loss; however, few studies have examined temporal relationships between changes in SE and body weight. Body weight and SE, quantified by the Weight Efficacy Life‐Style Questionnaire, were measured every 6 mo in 40 overweight adults (35 ± 5 yr, BMI 28 ± 2 kg/m2) participating in a 12 mo energy restriction study. All food was provided at energy levels of 10% or 30% below weight maintenance needs for 6 mo (phase1). Thereafter, food was self‐selected, but participants were instructed to maintain energy restriction (phase2). During phase 1, weight change was inversely associated with change in total SE (r = −.60), and in availability (r = −.50; AVAIL), social pressure (r = −.68), and positive activities (r = −.47; PA) subscales (P &lt; 0.01 for each). The phase1 changes in total SE (r = −.35), AVAIL (r = −.45) and PA (r = −.37) were each inversely associated with weight change during phase2 (P &lt; 0.05 for each). However, only AVAIL change during phase1 was a significant predictor of phase2 weight change in multivariate models ([β ± SEM] −0.25 ± 0.11, P &lt; 0.05). In conclusion, improvements in SE coincide with weight loss; intervention strategies targeting the situational dimension of availability, a construct capturing self‐efficacy for controlling eating in food‐rich environments, may deter weight regain. Funding source NGA 3U01‐AG20478 (NIA).

Correlation of a self-report and direct measure of physical activity level in the electron-beam tomography and risk assessment among Japanese and US Men in the post World War II birth cohort (ERA JUMP) study.

BackgroundPhysical activity (PA) is complex and a difficult behavior to assess as there is no ideal assessment tool(s) that can capture all contexts of PA. Therefore, it is important to understand how different assessment tools rank individuals. We examined the extent to which self-report and direct assessment PA tools yielded the same ranking of PA levels.MethodsPA levels were measured by the Modifiable Activity Questionnaire (MAQ) and pedometer at baseline among 855 white (W), African-American (AA), Japanese-American (JA), and Korean (K) men (mean age 45.3 years) in 3 geographic locations in the ERA JUMP study.ResultsKorean men were more active than W, AA, and JA men, according to both the MAQ and pedometer (MAQ total PA [mean ± SD]: 41.6 ± 17.8, 20.9 ± 9.9, 20.0 ± 9.1, and 29.4 ± 10.3 metabolic equivalent [MET] hours/week, respectively; pedometer: 9584.4 ± 449.4, 8363.8 ± 368.6, 8930.3 ± 285.6, 8335.7 ± 368.6 steps/day, respectively). Higher levels of total PA in Korean men, as shown by MAQ, were due to higher occupational PA. Spearman correlations between PA levels reported on the MAQ and pedometer indicated positive associations ranging from rho = 0.29 to 0.42 for total activity, rho = 0.13 to 0.35 for leisure activity, and rho = 0.10 to 0.26 for occupational activity.ConclusionsThe 2 assessment methods correlated and were complementary rather than interchangeable. The MAQ revealed why Korean men were more active. In some subpopulations it may be necessary to assess PA domains other than leisure and to use more than 1 assessment tool to obtain a more representative picture of PA levels.

Can the IPAQ-Long be Used to Assess Occupational Physical Activity?

To be able to draw any conclusions regarding the health effects of occupational physical activity (OPA), more information is needed regarding valid measures to assess OPA. Aims were to compare OPA as assessed with the International Physical Activity Questionnaire long version (IPAQ-L) with OPA assessed with an accelerometer and to assess the contribution of OPA to total PA. Working adults (n = 441; mean age = 49.4 yrs; 44% males) wore an accelerometer for 7 days in free-living situations and completed the IPAQL. Comparisons were made between IPAQ-L-work and accelerometer data limited to working time (Moderate and Vigorous PA (accelerometer-MVPA-work) and average intensity). Subgroup analyses were performed. Spearman correlation was r = .46 (P < .01) between IPAQ-L-work and accelerometer-MVPA-work. Correlations ranged from r = .27 to r = .55 in respectively obese and overweight subjects. The contribution of IPAQ-L-work to IPAQ-total was 24.7%. The IPAQ-L work domain is a moderately good measure of time spent on MVPA at work and can be used to assess the contribution of OPA to total PA. This study provides valuable information regarding the use of the IPAQ-L in assessing work domain specific PA, and underscores the importance of assessing OPA, as it can contribute for a substantial part to total PA.

ERROR BOUNDS FOR SURFACE AREA ESTIMATORS BASED ON CROFTON’S FORMULA

According to Crofton's formula, the surface area S(A) of a sufficiently regular compact set A in Rd is proportional to the mean of all total projections pA (u) on a linear hyperplane with normal u, uniformly averaged over all unit vectors u. In applications, pA (u) is only measured in k directions and the mean is approximated by a finite weighted sum bS(A) of the total projections in these directions. The choice of the weights depends on the selected quadrature rule. We define an associated zonotope Z (depending only on the projection directions and the quadrature rule), and show that the relative error bS (A)/S (A) is bounded from below by the inradius of Z and from above by the circumradius of Z. Applying a strengthened isoperimetric inequality due to Bonnesen, we show that the rectangular quadrature rule does not give the best possible error bounds for d =2. In addition, we derive asymptotic behavior of the error (with increasing k) in the planar case. The paper concludes with applications to surface area estimation in design-based digital stereology where we show that the weights due to Bonnesen's inequality are better than the usual weights based on the rectangular rule and almost optimal in the sense that the relative error of the surface area estimator is very close to the minimal error.

Self-Reported Physical Activity Patterns Among Low-Income Latina Women In Arizona

Adherence to recommendations for PA among adults in the US is poor, particularly among low-income Latinos. In 2009, 53.6% of Hispanics nationwide did not meet the guidelines for 30 minutes of moderate intensity activity on most, if not all, days of the week. In particular, Latina women are at increased risk for inactivity and chronic illness, but national health survey reports aggregate data across demographic strata, limiting descriptive information that could guide targeted PA promotion. PURPOSE: To determine PA patterns among a very low-income, low acculturated group of Latina women in the southwestern US. METHODS: As part of a large community intervention trial to increase cancer prevention behaviors, PA data were collected from 1,006 Latina women (mean age 39.3 +/- 13.8 years) using a modified version of the Arizona Activity Frequency Questionnaire (AAFQ). RESULTS: At baseline, the total average daily PA reported in minutes was 89.98 (+/- 147.71) for those reporting any exercise (10% reporting no exercise). Per specific activity, the total average daily minutes were: Walking, 44.11 (+/- 11.60; n=498); Jogging, 11.05 (+/- 28.68; n=165); Dancing, 17.78 (+/- 40.53; n=258); Light yard work, 19.99 (+/- 40.53; n=445); Lifting, 43.01 (+/- 85.25; n=397); Heavy yard work, 40.79 (+/- 85.49; n=45); Cleaning, 80.42 (+/- 111.51; n=305); Biking, 8.35 (+/-5.65; n=73); and Swimming, 25.59 (+/- 31.70, n=57). In categories with >300 participants reporting PA (Walking, Lifting, Light yard work, Cleaning), there is a bimodal distribution showing very low and very high levels of PA. CONCLUSION: In this sample Latina women, the average daily PA minutes/day exceeds the current PA recommendations. PA categories for which women reported highest levels of activity are those that may be tied to very active jobs. Among the lowest income Latinas, differences in low and high levels of PA suggests the need to target PA promotion efforts to population segments with differing profiles.

Family Matters: Specific Type(s) of Family Support in Adolescent Physical Activity Levels

PURPOSE: This study investigates the relationships between five types of family support and adolescent PA levels during periods of time when adolescents have more control (or agency) over the activities in which they participate, i.e., after school and weekend hours. METHODS: In a sample of 291 adolescents (144 females, 147 males), seven psychosocial variables were examined in relation to accelerometry-derived PA measured after school and during the weekend. Psychosocial variables were measured via a questionnaire based on Welk's (1999) Youth Physical Activity Promotion Model. The Actigraph 7164 was used to obtain PA measures, i.e., agency moderate-to-vigorous PA (MVPA) and agency total PA. Co-variates included % BF measured using a Hologic DXA scanner, centered age, and maturity predicted using the Mirwald equations. Spearman correlation coefficients were used to assess bi-variate associations. Stepwise linear regression analyses with forward selection were conducted to determine which combinations of the study variables (psychosocial indices, type(s) of family support, co-variates) explained the variance in Agency MVPA and Agency TA. The p-value was set at < 0.05. RESULTS: For adolescent females, % BF and maturity were significant co-variates, while centered age and % BF were significant co-variates for adolescent males. Family support demonstrated the strongest associations with female and male adolescent Agency PA variables (r = 0.27 to 0.40). Stepwise linear regressions revealed that being praised by a family member and % BF explained 13% of the variance in adolescent female Agency MVPA, while being praised and maturity explained 7% of the variance in Agency TA. For adolescent males, having a family member watch him participate combined with % BF and centered age to explain 13% of the variance in Agency MVPA, while having a family member participate with him explained 6.4% of the variance in Agency TA. CONCLUSION: Public health officials should encourage family members to provide specific type(s) of support in an effort to positively alter adolescents' PA behavior during agency times. Supported by the National Institute of Dental and Craniofacial Research (R01-DE12101; R01-DE09551); General Clinical Research Centers Program (M01-RR00059); National Center for Research Resources (UL1 RR024979)